Desired performance objectives of personal care absorbent products include low leakage from the product and a dry feel to the wearer. However, absorbent products commonly fail before the total absorbent capacity of the product is utilized. An absorbent garment, such as an incontinence garment or disposable diaper, often leaks at the leg, top-front or top-back areas of the diaper. Leakage can occur due to a variety of shortcomings in the product, one being an insufficient rate of fluid uptake by the absorbent system, especially on the second or third liquid surges.
Attempts to alleviate leakage include providing physical barriers with elastic leg gathers and changing the amount or configuration of the absorbent material at the zone of the structure into which the liquid surges typically occur. To further reduce leakage, articles with elasticized leg gathers have further incorporated additional, elasticized containment or barrier flaps located at the interior of the structure. Absorbent gelling particles have also been included to increase the liquid holding capacity in various regions of the absorbent structure.
Absorbent articles have typically employed various types of absorbent pads composed of cellulosic fibers. Particular absorbent garments have been configured to control the distribution of absorbed liquids. For example, an absorbent article can have a liquid permeable transport layer which is located between a topsheet layer and an absorbent body. In other configurations, a conventional absorbent member can have fluid storage and acquisition zones composed of cellulosic fluff mixed with absorbent gelling particles; and may include a dual-layer absorbent core arrangement comprising a bottom fluff pad containing hydrogel particles, and a top fluff pad with little or no hydrogel particles.
Non-woven materials such as carded webs and spun-bonded webs, have been used as the body-side liners in absorbent products. Specifically, very open, porous liner structures have been employed to allow liquid to pass through them rapidly, and help keep the body skin separated from the wetted absorbent pad underneath the liner. Some structures have incorporated zoned surfactant treatments in preselected areas of the liners to increase the wettability of the preselected regions and thereby control the amount of liquid wet-back onto a wearer's skin. In addition other layers of material, such as those constructed with thick, lofty fabric structures, have been interposed between the liner and absorbent pad for the purpose of reducing wet-back.
With conventional fluff-based absorbent structures, such as those discussed above, the cellulosic fibers, when wetted, can lose resiliency and collapse. As a result, the liquid uptake rate of the wetted structures may become too low to adequately accommodate subsequent, successive liquid surges. Where absorbent gelling particles are incorporated between the fibers to hold them apart, the gelling particles swell and do not release the absorbed fluid. Swelling of the particles can then diminish the void volume of the absorbent structure and reduce the ability of the structure to rapidly uptake liquid.
The addition of more absorbent material, such as secondary fluff pledgets, or absorbent gelling particles, has been employed to increase holding capacity. The desired rate of liquid intake within such arrangements, however, may not be sufficiently sustained during successive liquid surges.
Despite the development of absorbent structures of the types surveyed above, there remains a need for improved absorbent structures which can adequately reduce the incidence of leakage from absorbent products, such as disposable diapers. There is a need for an absorbent structure which can provide improved handling of liquid surges and more effectively uptake and retain repeated loadings of liquid during use.